The influenza virus (which causes influenza or the fluâ€), is an instance of a pathogen with a number of different hosts. The influenza virus can infect individuals, birds, pigs and totally different animals. It may survive in these animals even if all people had been someway made immune. Which signifies that even if a vaccine towards all strains of the influenza virus existed, one would nonetheless must immunize all people, pigs and even wild birds to eradicate influenza. Legionnaires’ sickness normally strikes center-aged people, though circumstances have been reported in all age groups. The sickness steadily happens in people whose resistance to